Known towel dispensers (inter alia EP-A1-0 283 544) require a threading-in of the cloth and an additional winding around a roller when they are used. In order to prevent the end of a towel roll from being used several times, the end is retracted as soon as it would hang freely, i.e. as it is wound off from the clean towel roll. The force required for the retraction is stored in a spring drive; to this end, however, the energy for the retraction of the respective portion of soiled towel has to be built up and made available. Each time the towel roll is changed, therefore, the supply or delivery roller is wound up manually in the correct direction for the cloth, and this results in frequent problems. After the winding up has taken place, a certain length of unused cloth must consequently be drawn off for the initial loading of the stored spring force, so that the first used portion is already drawn in and an excessively long loop hanging out of the dispenser is not formed. In the event of breakdowns in the dispenser the drawn-in cloth cannot be withdrawn; it must first be completely unwound onto the soiled roll and is thus lost.
Experience has shown that the above-mentioned conditions for the correct loading of a dispenser with cloth are the cause of numerous breakdowns, which constitute a sequence of lack of understanding, incapability, erroneous interpretation and false alarms and very often put a dispenser out of action for this reason. Since a premature changing of the rolls results in the loss of the cloth not yet used and because of the inherent susceptibility of these dispensers to breakdown, it has been suggested that two towel units, and in practice two complete towel dispensers, should be constructed one beside the other and should be coupled to each other mechanically in order to increase the operational readiness of the entire unit.
A threading-in of a towel which is at least partially automated is likewise known (W-OA1-96/32874). It has been found, however, that a dispenser of this type either requires auxiliary energy and/or special measures at the end of the towel, which have an adverse effect on the washing process
In addition, it has been found to be disadvantageous that in the case of the dispenser according to EP-A1-0 283 544 the roll of soiled cloth can roll off by vigorous pulling on the rear part of the loop, since the slip clutch required for the return of used fabric--for forming a temporary loop sufficient for drying--cannot put up an adequate resistance.
The object of the invention is therefore to provide a compact towel dispenser which does not have the drawbacks mentioned above. In particular, with a minimum of necessary instruction to the maintenance staff, a towel dispenser in accordance with the invention should provide the user with a maximum possible degree of operational reliability and hygiene. The dispenser should keep ready the available roll of towel in optimum portions and permit neither deliberate nor undesired multiple use of the towel. In particular, the roll of towel thereof has to be easy to change, i.e. it should be easy to load in the dispenser. In the event of a possible premature change of the towel roll it should not be necessary to re-wind the towel.
The necessary operations should not require any instructions. No extraneous energy should be necessary; and the dispenser's operations should have a high degree of reliability.
For hygiene considerations the used cloth and the clean cloth must be guided completely separately from each other over the entire conveying path. In addition, the cycle times of the dispenser should be reproducible and adaptable to what the users are used to, i.e. it should be possible for the same type of towel dispenser to be used in a manner which is satisfactory in every respect for a wide range of use environments, such as from the requirements of an old-peoples home, through a central administration of a bank to a fast-food restaurant on a motorway.
Furthermore, the dispenser must be suitable and economical for mass-production manufacture; for space considerations and cost, appliances arranged one beside the other are not desired.
The strip material used as the towel should not as a rule require any steps or changes with respect to that in existing dispensers installed and used in numerous locations, since further use is to be made of the existing infrastructure such as washing machines, mangles and drying plants, as well as the existing logistics associated therewith. A dispenser in accordance with the invention should not, however, be restricted to the use of textile strip material; it should be capable of being adapted to any environmentally acceptable, durable material.